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Programmable AC/DC Lithium-ion Battery for High-voltage Applications



OBJECTIVE: Reconfigurable, software programmable AC/DC Lithium-ion battery modules and packs capable of supporting high-voltage ground vehicle and robotic applications.

DESCRIPTION: Developing next generation electric based ground vehicles will require a battery module in the 24 V to 60 V range that can be assembled into a high voltage pack up to 1000V.Emerging military hybrid vehicle platforms, such as the Robotic Combat Vehicle (RCV) or Optionally Manned Fighting Vehicle (OMFV), will require high-voltage battery packs with the following expected characteristics: nominal voltage from 450 to 600 V, continuous power capability of 250 to 400 kW, and 25 to 100 kWh installed energy.Currently, in an electric- or hybrid-electric vehicle system, power electronics are required to convert between all of the different AC and DC voltages required by the various components, such as the AC motors and DC battery.These electronics include DC-DC converters, AC-DC rectifiers, DC-AC inverters, chargers, and motor drive controllers, and each extra component contributes to power losses and packaging inefficiencies.In the solar panel sector, AC batteries which are composed of energy storage coupled with micro-inverters are available as an alternative to having a large external DC-AC inverter to connect the DC energy storage source to the AC loads and provide enhanced space & power efficiencies.Accordingly, innovative solutions must be developed and demonstrated for vehicle high-voltage mobility batteries which will allow for a fully reconfigurable & software programmable AC/DC Lithium-ion battery, which can source and sink various DC & AC voltages with higher power, thermal, & packaging efficiency.Technology developed shall allow for direct charging of the AC/DC Lithium-ion battery off of a wide variety of both DC (ex: 28V, 50V, etc.) and AC sources (ex: 120VAC, 480VAC, etc.). The AC/DC Lithium-ion battery shall also allow for direct connection to an electric motor, or other AC loads, without need for an inverter or motor controller (single & three-phase AC).Technology developed to allow AC/DC variable operation should be fully integral to the battery and shall consider balancing/equalization, reliability, high-voltage safety, and capacity utilization.Technology developed should be scalable to 24V – 60V modules composed of a few cells to a few hundred cells, and should support pack configurations up to 1000V.

PHASE I: Identify and determine the engineering, technology, and embedded hardware and software needed to develop this concept. Drawings showing realistic designs based on engineering studies are expected deliverables. Additionally, modeling and simulation to show projected performance and Ah capacity of the AC/DC Lithium-ion battery modules & pack designed in this phase is expected.Cost analysis projections should also be performed to determine the cost premium between a standard battery system with external conversion electronics and an AC/DC Lithium-ion battery pack (<20% increase in overall product cost).A bill of materials and volume part costs for the Phase I design should also be developed.This phase also needs to address the challenges identified in the above description, including scaling to higher voltage packs.

PHASE II: Develop and integrate prototype embedded hardware and software to create AC/DC Lithium-ion battery modules and packs for high-voltage mobility applications.The AC/DC Lithium-ion battery modules shall interconnect to support series and parallel configurations in a battery pack and shall meet the following minimum requirements: 1.5 – 4 kWh, 10 – 25 liters, <60 kg, 20 – 25 kW peak power, 24 – 60 V, 5 to 10 C-rate, and -30 to 60°C operation with thermal management.Each module shall have a digital communication interface that supports at a minimum high-speed ISO 11898 CAN communication, as well as any other isolated digital communication protocols (e.g. SPI) necessary for operation of the battery module in a high voltage battery pack.Testing should be performed on AC/DC Lithium-ion battery modules and packs to demonstrate operation, performance, and Ah-capacity.Cost analysis should also be performed on the finalized product to determine the cost premium between a standard battery system with external conversion electronics and an AC/DC Lithium-ion battery pack (<20% increase in overall product cost).A bill of materials and volume part costs for the Phase II design should also be developed.Deliverables include electrical drawings and technical specifications, software, M&S and test results, and one AC/DC Lithium-ion battery pack (nominal voltage from 450 to 600 V) composed of reconfigurable, programmable AC/DC Lithium-ion battery modules.The pack battery management system (BMS) shall have at a minimum two SAE J1939 interfaces to support communication to the vehicle.

PHASE III: This phase will begin installation of the AC/DC Lithium-ion battery packs using the solutions developed in Phase II on selected vehicle platforms (military, commercial EV/HEV, etc.) and will also focus on integration of Phase II embedded hardware and software technologies into the production processes of current Li-ion batteries.

KEYWORDS: Lithium-ion, batteries, power, energy, battery management systems, CAN bus, low-voltage, high-voltage


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